The All Angles Design/AAD Performance Air/Oil Separator (aka Catch Can) was designed from the ground up to be the most functional, most flexible, and most reliable AOS available.
We worked hard to keep costs under control, but being "cheap" was never the goal - there are tons of inexpensive Catch Can options on the market. We wanted to build an AOS for the enthusiast who understands the value of keeping oil out of their high-performing engine.
We made ours the most functional Air/Oil Separator on the market by including both a coarse pre-filter (the lower filter on the unit) as well as a finer filter before the outlet. We further improved functionality by inducing a circular flow path through the unit which accelerates the oil droplets as they go through the filters causing them to either stick to the interior wall, or to the filter element itself - then drain into the reservoir below. We made both filters out of metal so that they never plug, last a lifetime, and are easy to clean if and when needed.
We made it the most flexible with a 3-piece, modular design. The top cap and center body can be rotated with respect to each other into any of 8 positions. This allows you to have your inlets coming from one direction with your outlets going some other direction. The powder-coated steel mount plate between them can be indexed separately from either of those pieces as well. So, your mounting options are primarily limited by your imagination (and possibly patience!).
Last but not least, we made it easy to use with our one-of-a-kid twist-off reservoir. That idea occurred to me one day at the track while slowly un-threading a catch can reservoir full of hot oil and waiting for that last thread to let go so I could tar and feather myself. With our setup, there is no drama - twist the can clockwise and it's on, counter-clockwise about 10 degrees and it clicks off. Stainless steel pins, springs, and snap rings make the magic happen and will outlast us all.
So, if you want a cheap catch can - by all means buy a cheap catch can! If you want the best available, buy an AAD Performance!